This application addresses broad Challenge Area (05) Comparative Effectiveness Research and specific Challenge Topic, 05-AR-102: Comparative Effectiveness (CE) of Treatments for Chronic Childhood Arthritis and Musculoskeletal (MSK) and Skin Disease. Infantile hemangiomas (IH) are the most common tumor of infancy, occurring in 1-5% of the children, yet no FDA approved treatments exist. The primary objective of this proposal is to develop a research platform to develop (1) standardized nomenclature for disease severity and (2) instruments to measure response to therapy to guide the design of studies. This objective will be achieved by first creating a research infrastructure, the Hemangioma Investigator Group Research Core (HIG-RC), to provide support in the areas of research design, implementation, and data interpretation. A hemangioma- specific severity scale system and a health-related quality of life (HRQL) instrument for IH will be developed, piloted, and validated by the HIG-RC. Our proposal will establish a sustainable infrastructure that uses an evidence-based approach to design, implement, and evaluate potential research and/or practice changes to improve treatment for IH. This research program has the potential to improve quality of life, decrease disease burden, and decrease health care costs. 7. Project Narrative Approximately 80,000 children are diagnosed with hemangiomas each year in the United States;12 % (9,600) of those are significantly complex requiring referral to specialists for consideration of treatment. Given the continued increase in the rate of low birth weight infants in the United States (8.2 % 2005) and the strong association with low birth weight and the development of hemangiomas (25% increased risk of developing a hemangioma with every 500 gm reduction in birth weight), the incidence will likely continue to rise. Complications of hemangiomas include permanent disfigurement, ulceration, bleeding, loss of vision, airway obstruction, congestive heart failure and very rarely death. Standardized outcome measures are lacking, creating a significant obstacle to clinical trial development.